Release of a new set of lines of an elite variety of wheat with deletions in Glu-B1 Locus (GluB1-S261A)

Authors: L Chingcuanco, Debbie

Submitted to: Germplasm Release
Publication Type: Germplasm Registration
Publication Acceptance Date: 7/12/2018
Publication Date: 4/12/2017
Citation: Chingcuanco, D.L. 2017. Release of a new set of lines of an elite variety of wheat with deletions in Glu-B1 Locus (GluB1-S261A). Germplasm Release. 8(1):1-8.

Interpretive Summary:

Technical Abstract: GluB1-S261A was identified from a fast-neutron radiation (FNR) mutagenized population of ‘Summit’, a commercial bread wheat variety developed by Resource Seeds, Inc, Goshen, CA which was acquired by Syngenta in 2008. Summit seeds used for mutagenesis was provided without restrictions to USDA in 2004 by its developer, the late Dr. Robert Matchett. Summit is a product of hybridization between ‘Express’ and ‘Tadorna’/’Proband775’. Express is a variety from Western Plant Breeders (Bozeman, MT), whereas Proband 775 is a variety from a company previously known as Northrup King, Co. (Minneapolis, MN). Tadorna is a Septoria leaf blotch (Septoria tritici) resistant line from the University of California, Davis. Summit was released in 2001 (PVP200200239, expires in 2023) and grown as one of the high yielding varieties in the Central Valley and surrounding areas in California. It later became susceptible to stripe rust and Septora leaf blotch. Stripe rust resistance genes Yr5 and Yr15 were introduced by four backcross generations into the susceptible cultivar Summit and released by Syngenta in 2011 as Summit 515. Summit expresses five high-molecular weight glutenin subunit (HMW-GS) genes from the following loci: GluA1a (Ax1+null), GluB1i (Bx17+By18), and GluD1d (Dx5+Dy10). These are considered as one of the best allelic pair combinations for bread baking. GluB1-S261A was identified by ARS scientists by screening M3 seeds for altered storage protein profiles using one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The GluB1-S261A deletion line is distinct from the wild-type progenitor by the absence of the HMW-GS Bx17 and By18 proteins encoded by the GluB1 locus. The absence of the Bx17 and By18 proteins in this line is due to a 154.81 cM FNR induced deletion in the long arm of chromosome 1B that includes the GluB1 locus. The inheritance of the Bx17 and By18 protein deficiency phenotype of GluB1-S261A is stable as evidenced by its consistent transmission to progenies of plants grown in the greenhouse. The morphological and developmental phenotypes of greenhouse grown GluB1-S261A is similar with those of its wild type Summit progenitor. More specifically, GluB1-S261A is a hard-red spring common wheat with erect plant growth, anthocyanin-less hollow stem, mid-dense tapering head with awned spikelets and florets with yellow anthers. The wild-type Summit progenitor is tolerant to stripe rust, speckled leaf blotch, leaf rust, barley yellow dwarf virus. However, these traits have not been evaluated in the GluB1-S261A deletion line. The release is targeted for use by domestic and international wheat researchers and wheat breeders. Genetic variations in the HMW-GS loci correlate well with dough quality. Different allelic pair combinations in the HMW-GS gene loci vary in their effect on dough properties. The gluten proteins including those encoded in the GluB1-S261A locus are known to contain immunogenic epitopes that cause gluten-related health risks e.g. celiac disease. GluB1-S261A, together with other glutenin deficient lines, will be used to develop wheat varieties with altered seed protein composition with modified dough functionalities and to develop wheat-derived products with reduced immunogenic potential.